The role of quality of life in functional gastrointestinal disorders: Regulatory issues

Generic questionnaire such as SF36 and functional gastrointestinal disorder (FGD)- specific questionnaires (i.e. IBSQOL or FGDQL) are now available fo r the evaluation of new drugs for the treatment of irritable bowel syndrome or functional dyspepsia. For regulatory issues it is necessary to describe in detail the scale of the QOL questionnaire, its psychometric properties and reason for its choice, as well as validation studies, populations conce rned, means of administration and methods for analysis. Preselection of few dimensions of the QOL questionnaire, if necessary, has to be explained. QO L results have to be compared with symptom scores. Trials have to be double -blind placebo- controlled studies with a sample size calculation taking ac count of the high placebo-response. No official guidelines are available in FGD and more validation studies are needed to help in the choice of the sp ecific QOL questionnaire, in the metrologic analysis and in the interpretat ion of QOL changes during FGD treatment. Then QOL questionnaires could beco me a primary end point in clinical trials if efficient drugs for FGD treatm ent are developed.